Ham

@gershbrain.bsky.social and I have a new paper in PLOS Comp Bio!

We study how two cognitive constraints—action consideration set size & policy complexity—interact in context-dependent decision making, and how humans exploit their synergy to reduce behavioral suboptimality.

osf.io/preprints/ps...

Kempner Research Fellowship - Kempner Institute The Kempner brings leading, early-stage postdoctoral scientists to Harvard to work on projects that advance the fundamental understanding of intelligence.

If you work on artificial or natural intelligence and are finishing your PhD, consider applying for a Kempner research fellowship at Harvard:
kempnerinstitute.harvard.edu/kempner-inst...

Social inequity disrupts reward-based learning - Communications Psychology People learn from rewards differently when outcomes are shared with others. Learning slows when receiving smaller reward shares, and social stereotypes about partners further impair learning when cogn...

People learn from rewards differently when outcomes are shared with others. Learning slows when receiving smaller reward shares, and social stereotypes about partners further impair learning with cognitive demands.
@hamhuang.bsky.social @annajenkins.bsky.social
www.nature.com/articles/s44...

Great mentor! Can’t go wrong!

Imagine this scenario: would you rather me giving $2 to you and $1000 to a politician or not giving you or the politician any money at all? Many people would choose the latter option, even though the first option gives them more monetary benefits.

People don’t always choose the option with more money because what people find rewarding is not simply the amount of money, but also social equity. When deciding which option is more rewarding, people consider both the amount of money and the inequity.

However, making decisions is different from learning from rewards. People always know which option feels more rewarding to them when making decisions, but learning from reward can happen very implicitly. People learn to choose the rewarding options without knowing it.

How can social inequity matter if people may not even realize that they learned from reward? We found that surprisingly, it matters! A lot! This suggests that social inequity profoundly impacts reward representation at all levels.

In 3 experiments (N=280), subjects tried to learn which of 3 keys gave more reward ($0, $1, or $2) in different contexts. The reward was split with another person. We manipulated the inequity level from 0% to 100%. The keypress only determined the total reward.

We found a huge inequity effect. When subjects received less than 50% of the reward, they learned more slowly and less effectively. Moreover, they were more sensitive to inequity levels under 50%. For example, 80% vs 90% made less difference to learning quality than 10% vs 20%.

We discovered that reinforcement learning is also socially contextual! We are currently working on an fMRI study to tackle follow-up questions about how the social brain ties to the learning brain, led by Mu-chen and in collaboration with Joe Kable. Stay tuned!

Social inequity disrupts reward-based learning - Communications Psychology People learn from rewards differently when outcomes are shared with others. Learning slows when receiving smaller reward shares, and social stereotypes about partners further impair learning when cogn...

🚨New paper!🚨My new work with @annajenkins.bsky.social is published
@commspsychol.nature.com
! Social inequity shapes people’s ability to learn from rewards during reinforcement learning! www.nature.com/articles/s44...

People don’t always choose the option with more money because what people find rewarding is not simply the amount of money, but also social equity. When deciding which option is more rewarding, people consider both the amount of money and the inequity.

Imagine this scenario: would you rather me giving $2 to you and $1000 to a politician or not giving you or the politician any money at all? Many people would choose the latter option, even though the first option gives them more monetary benefits.

Here is the full poster ;)

A lineup showing upcoming talks and posters for the CoLab at CogSci 2025. Wednesday Natalia Vélez: Understanding structural diversity in human collaboration Metareasoning Workshop, Pacific H, 10:30-11:10am Thursday Huang Ham: Collaborative encoding of visual working memory P1-H-244 Friday Bonan Zhao (new PI!): Discovering hidden laws in innovation by recombination P2-Z-231 Elizabeth Mieczkowski: A normative account of specialization: How task and environment shape role differentiation in collaboration P2-M-133 Bella Fascendini: Are two-year-olds intrinsically motivated to explore their own competence? Learning & Development 2, Salon 6, 1-2:30pm Saturday Renée Creppy (first-timer!): Children’s expectations of dominant and prestigious leaders P3-C-40 Natalia Vélez: Thinking in teams Invited Symposium: New Theoretical Directions in Cognitive Science Salon 7, 2:15-3:45pm

The CoLab is headed to #CogSci2025!! 🥳 Here's where to find us!

Collaborative Rational Speech Act: Pragmatic Reasoning for Multi-Turn Dialog As AI systems take on collaborative roles, they must reason about shared goals and beliefs-not just generate fluent language. The Rational Speech Act (RSA) framework offers a principled approach to pr...

"We introduce Collaborative Rational Speech Act (CRSA), an information-theoretic (IT) extension of RSA that models multi-turn dialog by optimizing a gain function adapted from rate-distortion theory."

arxiv.org/abs/2507.14063

Excited to see the work during my undergrad times finally come out! Learned so much from working with Sam and Anne on this project.

We are so excited to welcome our summer RA's to the lab! Looking forward to a productive summer💫 @bellafascendini.bsky.social @hamhuang.bsky.social @creppy-r.bsky.social